Question: What is libretto by Das Rheingold, which has a famous book called the Lohengrin?
Paraphrase: What is libretto by Das Rheingold, which has a famous book called the Lohengrin?
SPARQL (Wikidata): SELECT ?answer WHERE { wd:Q327717 wdt:P87 ?answer . ?answer wdt:P800 wd:Q23085}
Answer: Richard Wagner